In designing and erecting buildings, it is conventional to utilize spaced beams over which decking is applied and thereafter roofing is applied to provide the roof of the building. In such buildings, the heating and ventilating is usually added to the interior of the building.
Among the objects of the invention are to provide a building construction wherein substantial loads can be supported with minimum use of columns and wherein the heating and ventilating system can be incorporated in the roof structure without projecting into the interior of the building.